鄂尔多斯盆地直罗组赋铀沉积相与油气蚀变带的时空配置

Time-space configuration of uranium mineralization,sedimentary facies and oil & gas-induced alteration zone in Zhiluo formation,Ordos basin

本文依据酸解烃特征参数C1/∑C、C1/C2+及酸解烃判别分析(Z值法、Φ值法及判别因子法),论证了赋存于直罗组地层中的烃气来源于三叠系上统湖相生油岩系中与油型气同源而伴生的凝析气藏,论述了直罗组下段的褪色蚀变(漂白)是渗逸到该层位中的酸解烃类气体对岩石发生蚀变作用的结果,提出沉积相组合与油气阻滞-储集域的空间配置是油气蚀变带与铀矿化层位空间定位的制约因素。

According to characteristic parametersC1/∑C and C1/C and discriminatory analyses （Z value method, φvalue method and discriminatory factor method） of acidolysis hydrocarbon, this paper demonstrates that the hydrocarbon gas in Zhiluo formation is from the accompanying condensate gas reservoir with the same source to oil-type gas in lacustrine source rocks of Upper Triassic, dissertates that the discolored alteration （bleaching） in the lower member of Zhiluo formation is the result of induced alteration of rocks due to infiltrating of acidolysis hydrocarbon gas into this horizon and presents that the sedimentary facies association and spatial configuration of oil ＆ gas blocking-reservoir domains are constraint factors to oil ＆ gas-induced alteration zone and space orientation of uranium mineralization horizons.